mig welder suggestions

[Catbird]

90% of the wire feed welding I did was on mild steel and virtually all of that was done with ER70S wire shielded by C25 gas.

ER70S stands for:

Electrode - suitable for use as an electrode (carrying the welding current)
Rod - suitable for use as a filler rod for TIG or oxy/acetylene welding
70 - 70,000 lbs tensile strength
S - solid wire (not flux cored)

C25 is 25% carbon dioxide and 75% argon

Most wire feed welders have a chart inside the door covering the spool and feed mechanism. This will have recommended settings for feed speed and voltage for given material thickness. It usually has recommendations for shielding gasses as well. It should look something like this:

weld chart.jpg

[Netpackrat]

I use the c25 now. When I bought my machine, I had this old bottle of CO2 left over from when my family owned an auto body shop, and it took me a while to use it up. Welds with the C25 are MUCH nicer, and it produces far less splatter.

[Les Nessman]

Good info. Thanks guys.
Years ago, when I worked in a weld/machine shop I seem to recall that we mostly used 75/25 CO2Ar (C25).
IIRC, the bottles were about 5' tall and were heavy as hell.

I think there are smaller bottles available.

[Netpackrat]

I have two of the 125cf bottles of the C25. When one goes empty, I swap it out and keep working, and get the other one refilled later. My CO2 bottle was around 300cf, but it was heavy and a real pain, and too big for a reasonable size cart. The welding supply place was happy to give me full credit for it against the two smaller bottles. I know it's more expensive to buy my gas in the 125s, but the convenience is worth it, and I still don't have to swap the bottles very often.

My TIG unit, on the other hand, likes to go through argon, so I usually use a 300cf bottle for that.

[Darrell]

Ever have a problem with 25/75 separating? I was getting crappy looking welds with lots of spatter, and talked with one of the guys at the welding supply shop. He said if the bottle isn't in use regularly, the CO2 can separate from the argon--one goes to liquid, the CO2, I think, while the argon remains gaseous. He suggested agitating the bottle, laying it down on the floor (with the cap on, of course) and rolling it around. Was he pulling my leg?

[Catbird]

He said if the bottle isn't in use regularly, the CO2 can separate from the argon--one goes to liquid, the CO2, I think, while the argon remains gaseous.

It separated out at 1 G and room temperature? That's a really advanced idea. Not very likely unless it's sitting in a methane snowbank.

If the machine is set up properly, the most likely culprit is that the bottle is filled with the wrong gas or mix of gasses, (it happens).

[Netpackrat]

Ever have a problem with 25/75 separating? I was getting crappy looking welds with lots of spatter, and talked with one of the guys at the welding supply shop. He said if the bottle isn't in use regularly, the CO2 can separate from the argon--one goes to liquid, the CO2, I think, while the argon remains gaseous. He suggested agitating the bottle, laying it down on the floor (with the cap on, of course) and rolling it around. Was he pulling my leg?

Not saying it can happen, but if the CO2 were to separate and go liquid, then you'd be welding using straight argon, which should work supremely well for a shielding gas. If you used up all the gaseous argon and were welding with straight CO2, it would still work, you'd just get more splatter and you welds might not be quite as nice, but in all likelihood would not classify as crappy. I'd vote for something else being the problem.

I haven't had any such problems with my current bottle of C25, which sat all winter out in my shed at below freezing temperatures.

[ButchS1066]

Have to agree with NPR's accessment. I use C25 on my MIG setup and either pure argon or an argon/helium mix on my TIG setup. Pure argon works just fine on a MIG welder, so if C25 did somehow manage to seperate I'd doubt you'd notice a difference till the argon was used up.